'People say: 'How can you deal with teenagers?' But try dealing with women in their 70s," laughs Susan Langford. In an airy room in east London, a group of teenagers and older women are looking at piles of brightly coloured portraits in between giggling and chatting. But it's not the young girls laughing and teasing their new friends; it's the older women who are irrepressible.

Langford's charity Magic Me was set up in 1989 to break down generational barriers through creative projects. It certainly seems to work: the all-female group I meet – ranging in age from 14 to 80 – collapse with mirth when they read back the teenagers' comments about what they expected the older women to be like before they started a four-month art project together.

"Boring," one wrote. "Bad tempered" was another favourite – oh, and "snoring when they sleep". "But we do snore. I snore when I think I'm awake," points out Roberta, plaintively. "It just seems to happen lately, just all of a sudden … zzzz" – she mimes falling asleep to more gales of laughter.

Brought together once a week for The Moving Lives project, the older women from the borough of Tower Hamlets and teenagers from the local Mulberry School for Girls created an audio-video installation inspired by the collections at the nearby Women's Library, which, to their obvious pride, was then displayed there. But it's the new friendships they formed that have proved transformational.

Anisa Islam, a quiet 15-year-old, is passionate about the sessions, which she says have given her a safe place to talk about difficult emotions. "One day we had to bring something in from our rooms and I brought a poem my sister wrote when she was in hospital. She's sadly passed away now and I keep it as a memento. I told [the women] about it and it meant a lot to me that I could trust them."

Alongside the emotional support, there is much-needed practical guidance only older women can give, she says. "I am closest to Winnie [Roach]. She gives me a lot of advice – about GCSEs, telling me not to stress about it too much." Winnie, sitting next to her, nods in agreement, "They can confide in us and we will keep our mouths zipped."

And mixing with women of different ages has given the once-hesitant Anisa a newfound self-assurance, she says. "Before I was really shy and I couldn't talk up, but now I join in and am confident. I didn't think I would have anything in common with [the older women] but as soon as you get to know them you find out this isn't true."

Her headteacher, Vanessa Ogden, agrees that Magic Me, which has worked with the school on eight such projects, has had an extraordinary effect on the girls taking part. "Every year, every student blossoms in self-confidence and their ability to think about their lives. I think young girls learn an enormous amount from older women. They respect meeting women with life experiences, and begin to understand how they can shape their own lives. They regard them as role models."

The Moving Lives project is just one of a host of schemes Magic Me runs across London that bring together people of different age groups; from singing lessons for primary school students and care home residents, to cocktail nights for young adults and older people living in residential homes. Langford believes such projects are becoming essential, as the generations mix less often.

"There are not many places outside family groups where people congregate naturally and interact with one another that are truly intergenerational these days," she says. "Society is more age-divided than ever so there are few places where people have a chance to get to know each other. We miss out on variety and we are no longer used to talking to people who are different."

Such projects are especially important in Tower Hamlets, where rapid changes in the area's demographics – both in terms of age and ethnicity – has had serious consequences for community cohesion, says Langford. The borough is one of the UK's most deprived and the social makeup has been shaped by successive waves of migration; while Mulberry school has been deemed outstanding by Ofsted its makeup is reflective of the area – 95% of the pupils are from Bangladeshi backgrounds, most speak English as a second language and the proportion taking free school meals is five times higher than the national average.

"There's so much social mobility in the East End," says Langford, who was featured in Gordon Brown's book Britain's Everyday Heroes in 2007 thanks to her work with the charity. "New neighbours come in and people find it hard to get to know each other because of cultural differences; they are scared to go and knock on the door and introduce themselves, which they would have done in the past." For older people, this can lead to isolation, she adds. "If people have a bad experience with someone older or younger they get suspicious and worried. Tower Hamlets, especially, has an above-average young population and a smaller-than-average older population, so older people do feel quite outnumbered."

Social embarrassment can also stoke fear within communities, she points out. "One of the older [white] women who comes to a different project said she was in Whitechapel market when someone put their hand on her shoulder. She told me: 'A few years ago I would have jumped a mile.' But this time she didn't. She recognised that if an Asian woman had put a hand on her shoulder before the project she would have reacted differently."

Sue Mayo, the artist who leads the Magic Me groups at the library, says creating art together is important in helping the women and girls relax in each other's company and express themselves. "By 2007 we were aware that people were not mentioning the fact they came from different faith communities. So we introduced a theme, 'What is heartfelt for you', that allowed people to talk about it." And later, after the July bombings, young participants who wore headscarfs felt comfortable enough to open up about being harrassed or spat at on the street.

The women and girls of the Moving Lives project are clear that the group's diversity – the older volunteers include women with Jewish, West Indian and African origins, while some of the girls wear headscarfs, and others salwar kameezes – is a strength, because it means there are more opportunities to learn. Rachel Ogunleye, a lively 78-year-old, says she knew nothing about the second world war's effect on London before meeting Marion [Davies, one of the older volunteers], while Samira Begum, her 16-year-old friend, says she is entranced by Rachel's own tales of life as the daughter of a Nigerian chief. "It is fascinating – she was a princess!" she enthuses, before reflecting: "It's backgrounds, though, not cultural differences."

This year the group looked at the archives connected with suffragette Emily Wilding Davison, who died in 1913 after stepping in front of the king's horse at the Derby. The Moving Lives project created and displayed an interactive audio-video installation around the contents of her pockets – with some unexpected results. "When we first came to do a project here we were allowed to touch Emily's purse. Marion had never voted until that day, but after she held the purse and learnt about the suffragettes it got her thinking she should join in and she has voted ever since."

Davies, a glamorous woman with bright red lipstick, a leopardprint cane, and her white hair piled into a bun, says the benefits of schemes such as this are enormous for older and younger people alike. "I think there should be a Magic Me in every borough. When we first started, we looked at each other and thought, 'What can we possibly learn? We can't even talk to each other.'

"We were like strangers but by the end of the project we are like family. I look forward to seeing the girls and they look forward to seeing us. They have given me 20 years off my life, and they make me feel young again."

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